Apparatus for treating sugar



Ust. 14, 1924. nnw

' B.C.LECHLER APPARATUS FOR TREATING SUGAR Filed Jan. 15. 192i INVENTOR.

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:BRUNO C. LECI-ILER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO' FLETCHER WORKS, INCORPORATED, 0F PHILADELPHIA, PENNSYLVANLL, A COR- PORATION OF PENNSYLVANIA.

APPARATUS FOR TREATING SUGAR.

Application filed January 15, 1921.

To all whom t may cof/wem:

Be it known that I, BRUNO C. LnoHLnn, a citizen of the United States, and a resident of Philadelphia, in the county of Philadelphia and Commonwealth of Pennsylvania, have invented certain new and useful lmprovements in Apparatus for Treating Sugar, of `which the following is a specification.

lVly invention relates to an improved method of and apparatus for treating sugar and an obj ect of the invention is a reduction in the loss in centrifugal sugars due to inversion during `storage and transportation.

Centrifugal sugars, as is well known, are subject to gradual deterioration, depending upon the degree of moisture present and bacterial and mold contamination at the time of bagging. As the sugar magma is sterilized by heat incidental to the formation of the sugar crystals in a vacuum pan and thereafter isimmediately separated into centrifugal sugar and molasses, and as this sugar when bagged has but a limited opportunity to absorb either moisture or bacteria from the surrounding air, it is desirable to reduce or prevent the contamination of the sugar during the period beginning when 'the magma leaves the centrifugal and ending when it is bagged.

With the existing apparatus the centrifugals acting as fan rotors, draw great quantities of air into the centrifugal casing, a portion of which is necessarily drawn through the sugar, thus carrying away moisture and increasing the dryness of the sugar crystals but in this operation any spores contained in the air drawn through the sugar are deposited upon the wet faces of the crystalline mass. In practice this air is drawn in chiefly at the bottom of the casing and therefore comes in contact with air close to the floor and which has been shown to contain the largest percentage of these spores. These spores are of several types common in the raw cut cane and in the soil and are subject to propagation in stagnating masses of sweet wa-ter or ymolasses drippings on the floor.

Existing centrifugals cannotbe enclosed in an air-tight casing because means must be provided. for charging massecuite and removing molasses and sugar. Furthermore, the centrifugal spindle passing into the casing necessarily possesses a certain amount of Serial No. 437,486.

lateral motion. Even were it feasible to encase the entire centrifugal, provision would still have to be made for charging the massecuite, extracting the molasses, removing the sugar and cleaning the lining of the centrifugal, all of which requires frequent access to the machine and prevents the use of any elaborate devices requiring a considerable number of operations in placing the same in yposition and removing the `same to permit access to the centrifugal.

In the device of this invention no attempt is made to seal the centrifugal within its casing and although I prefer to provide the casing with hinged, sectional covers closing the top opening and thus reducing the access of air to the centrifugal, no eEort is made to seal the sugar or molasses discharge openings.

It is the purpose of the present invention to arrange my apparatus whereby air will be drawn into the same from a `point removed as far as possible from contamination, such as the upper part of the centrifugal room `where the air is comparatively undisturbed, or from without the room entirely, means having been provided whereby this air will be maintained free from contamination.

By my improved method and apparatus the air is drawn into the centrifugal by uti lizing the action of the centrifugal which acts as a fan rotor, this air being discharged through the molasses spout. Furthermore, by my improved method and apparatus not only is the air drawn into the centrifugal maintained free from contamination, but the sugar being discharged from the centrifugal is rcarried against this stream of air in a closed passage leading from the centrifugal, the sugar in passing through `this passage being brolren up into separa-te crystals so that each crystal is air dried. y

Inasmuch as in a centrifugal the drying of thecrystals is realized by the physical throwing off of mo-isture drops from the interstices between the crystals, hygroscopically or capillary retained moisture is but im# perfectly removed and this small remaining trac-e is removed to a much better advantage by a dry current of air. It `will be seen, therefore, that by my improved method and apparatus both the spore contamination and degree of moisture arereduced.

Y 50 transportingsugarto the closed passageway Broadly, therefore, my invention relates to a process for purging sugar which consists in subjecting the-sugar magma to centrifugalg force in a substantially sterile at- Y be-understood-that the apparatus illustrated in the accompanying drawing is merelyillus-` trative and not definitive.

Referring to the accompanying drawing, 1y designates a centrifugal basket driven from ya driveJ shaft 2 by! a suitable motor 3,

the centrifugalbeing 'surroundedlby a casing 4.' The centrifugal or centrifugal basket is providedy at its top with any opening 5- through Which-the inassecuite is charged to the basket and lan opening 6 in lthe bottom thereof through whieh the sugar is discharged vfrom y the basket,thisopening being controlledby charge of molasses from the basket betweeny a cover 7. The'sides of the basket are perforated as indicated atiS to allow the dis n thefbasket andthe casing fl, this molasses beingdiscliarged from vthe apparatus at the discharge spout '9.

The casing 4 lis provided with a sectional `cover 1(7)` and material is charged into the basket from a supply tank 11, the discharge of material from this basket being controlled by a- V valve 12. Steam is z xdinitted to the l centrifugal by means ofa steam pipe 13, the

supply of-stearn to the centrifugal being controlled byfa valve 111.. The lowerpart of the casing tis, connected with a closed passageway 15, inthe present instance directlybeneat-h the discharge opening 6 of the centrifugal basket, this passageway in operation being ,in communication with a closed I passageway .16,.the latter leading to a storr age rooinj-or bin 17 from. which the sugar is conveniently dischargedginto bags 181 The i closed' passageway 15 is provided with a v conveyer 1-9 driven by a motor 20, this conveyer. being provided for thev purpose of lgwfithin which ,I provide elevator -21 drivenjfrom any1-suitable source of power, and adapted toreceivethe sugar from the conveyer 19 'and elevate it to the storage bin 17. Thestorage bin ispro-vided with -a pipe 22 whieh may be Ilocated adjacent the Atop of thecentrifuga-l room or yconnectedto the outside atmosphere. The purpose of pro viding the 22 isto insure that Ia supplyl 'of' uncontaminated lair will be Vdrawn Linto the centri-fugaljinstead of taking the air from that :portionofI the room proximity to the centrifugal-as-is usually-done with apparatus new employed. If desired, steam pipes-*23`may be provided `near thepipe 22 so that `the air drawn into the apparatus may be heated. It is to be understood that the passageway/s 15 and 16 are closed and that all air drawn into the centrifugal must pass through these closed passageways and likewise that sugar passing from the centrifugal to the storage bin 17 must travel through these closed passageways also. It is to be understood furthermore that while I have illustrated a bin, et cetera, it may at times be feasible to discharge the sugar directly from the bottom of the casing l to some other point where the air is substantially uncontaminated and vfrom which the air passes backA through the centrifugal against the outgoing stream of sugar.

In operation the sections of the cover 10 of the casing are raised and the centrifugal basket lis charged with the sugar magma fromk the storage tank 11 and the covers closed. The centrifugal is then brought to speed whereupon the molasses is thrown out through the perforations A8 in the side walls of the centrifugalbasket, caught in the outer casing and carried off through the spout 9. `While the centrifugal is still in operation a jet of dry steam is passed into the centrifugal through the steam pipe 13, this jet serving both to sterilize and heat the sugar and to cause the film of molasses or mother liquor adhering to each crystal to :become more fluid and pass ofi' `more easily.

After -a suflicient period of time the valve 14 in the steam pipe 13 is closed, thus shutting off the supplyof steain to the centrifugal, the centrifugal basket however continuing to rotate and drawing in through the outlet 6 of the basket quantities ofuncontaminated or sterile air from the upper part of the bin 17 through the closed 16 and 15. This air which may be slightly heated if desired, being drawi'x through the sugar in the centrifugal basket will serve to carry away theinoistnre in the basket re maining from thecondensed steam and leave the crystals in as dry a condition as possible.`

The centrifugal is then stopped, the covers 10 opened, th-e 4cover or valve 7 at the bottoni lifted and the sugar discharged through the opening (5 in the closed passageway .15 upon theconveyer. The centrifugal may then be charged again and while in operationpthe sugar inthe passageway 15 will be agitated by the conveyer 19 and gradually conveyed to the closed passageway 1b where it will be lifted by the elevator 21 and carried up and discharged into the bin 17, the sugar in passing from the lcentrifugal to the'bin being subjected to the sterile ai-r passing from the pipe 22 to the-centrifugal, further drying of the sugar being effected for this reason and the sugar finallybeing bagged from the ,hin 17 directly, without further ycon-tact with spore laden air. v It will be seen, therefore, that I have ,pro-

assawewa s:

vided a process for purging sugar whereby the sugar is treated and bagged in an atmosphere substantially free of spores and that, therefore, the danger of inversion of the sugar during storage and transportation is eliminated.

What I claim is:

l. In an apparatus for purging sugar, in combination, a centrifugal provided with a casing which has separate charging and discharging openings, and means for preventing the entry of contaminated air to the centrifugal during operation of the same and during the discharge of material from the centrifugal.

2. In an apparatus for purging sugar, in combination, a centrifugal provided with a casing having both a charging and a discharging opening, means connecting one of said openings with a source of substantially uncontaminated air, said openings in the casing being so proportioned and disposed relative to the centrifugal as to cause the latter to draw air into the centrifugal through the opening connected with a source of uncontaminated air.

3. In an apparatus for purging sugar, in combination, a centrifugal provided with a casing, and an enclosed passageway leading from an opening in the centrifugal casing and communicating with a supply of substantially uncontaminated air.

4. In an apparatus for purging sugar, in combination, a centrifugal provided with a casing having charging and discharging openings, means for closing the charging opening, means for supplying dry steam to the contents of the centrifugal basket and an enclosed passageway leading from the discharging opening through which passageway dried material leaves the centrifugal and uncontaminated air enters the centrifn ugal.

5. In an apparatus for purging sugar, in

combination, a centrifugal and a centrifugal casing having discharge openings, a storage bin, a closed passageway leading from said discharge openings to said storage bin, a screw conveyer and an elevator cooperating therewith for transporting sugar crystals from the centrifugal discharge opening to the storage bin through said closed passageway, and means for drawing uncontamr nated air through said passageway in a direction opposed to the direction of travel of the sugar crystals through the passageway.

G. In an apparatus for purging sugar, the combination of a centrifugal and a centrifugal casing, a storage bin in communication with a supply of substantially uncontaminated air, a closed passageway connecting the centrifugal to the storage bin, means for conveying sugar crystals from the centrifugal through said storage passageway to said bin against a current of uncontaminated air passing from the bin to the cen trifugal and means for heating said current of air.

7. In an apparatus for purging sugar, the combination of a centrifugal and a centrifugal casing, a storage bin communicating with a supply of uncontaminated air, means for heating said air, a closed passageway connecting the centrifugal and centrifugal casing with said storage bin, means in said passageway for breaking up the sugar crystals discharged into the same from said centrifugal, and means in said closed passageway for conveying the sugar crystals after the same have been broken up to said storage bin, a current of uncontaminated, heated air from the supply bin passing through the mass of sugar cyrstals as the same is being conveyed to the storage bin.

This specification signed this 14 day of January 1921.

BRUNO C. LEGHLER. 

